The present invention relates in general to the use of industrial lasers and, more particularly, to a passive sealing arrangement for an enclosure which houses industrial lasers or like devices.
Industrial lasers are known in the prior art. Such lasers are commonly used for purposes of welding and cutting. U.S. and international standards have been developed which divide all industrial lasers into four major hazard categories, i.e., four broad classes (I to IV). The weakest lasers are Class I lasers which emit laser radiation below known hazard levels. The strongest lasers are Class IV lasers which are hazardous to view under any condition (directly or diffusely scattered) and are a potential fire hazard and a skin hazard.
Laser enclosures are also known in the prior art. Such enclosures are commonly used as protective enclosures for higher powered lasers, e.g., Class II, Class III or Class IV lasers, and allow the higher powered lasers to operate in a lower classification. For example, some Class I industrial lasers consist of a higher class laser enclosed in a properly interlocked and labeled protective enclosure.
One laser enclosure found in the prior art encases a laser workstation. Associated with the workstation is a laser device which acts to generate and direct a laser beam to the workstation for performing laser operations upon workpieces that pass into the enclosure.
The noted laser enclosure comprises three stationary walls, a stationary ceiling and a fourth stationary wall having an opening through which workpieces pass into and out of the inner cavity of the enclosure. The enclosure includes a rotary turntable having four vertical partitions that attach to a hub at the turntable's center of rotation, which is coplanar with the fourth stationary wall. Positioned between the four vertical partitions are four fixtures for mounting workpieces onto the rotary turntable.
Portions of two of the vertical partitions are sealed to a portion of the fourth stationary wall by hinged flaps to inhibit the escape of laser radiation from the enclosure. Those flaps are moved between sealing and non-sealing positions by a plurality of pneumatic cylinders. It has been found that operation of the cylinders is time consuming, resulting in an undesirable pause occurring between laser operations. Accordingly, this active sealing arrangement is a substantial limitation on welding efficiency, especially where a succession of workpieces is to be welded.
There is therefore a need for an improved sealing arrangement which does not require active drive devices, such as pneumatic cylinders, to accomplish sealing. Furthermore, there is a need for an improved sealing arrangement which allows sealing to be accomplished in a quick and efficient manner.